/*

TagCloud jQuery plugin

A dynamic JavaScript tag/keyword cloud plugin for jQuery, designed to use with Ajax:
the cloud is generated from an array.

MIT license.

Schaffer Krisztián
http://woophoo.com

Usage:
------

Call it on a jQuery object created from one element and pass an array of
objects with "tag" and "count" attributes. E.g.:

var tags = [{tag: "computers", count: 56}, {tag: "mobile" , count :12}, ... ];
$("#tagcloud"}.tagCloud(tags);


Configuration:
--------------
Optionally you can pass a configuration object to tagCloud as the second
parameter. Allowed settings are:

sort: Comparator function used for sort the tags before displaying, or false if
   no sorting needed.

   default: sort by tag text using
          function (a, b) {return a.tag < b.tag ? -1 : (a.tag == b.tag ? 0 : 1)

click: Event handler which receives the tag name as first parameter
   and the original click event as second. The preventDefault() is called
   on event before passing so don't bother.

   default: does nothing:
          function(tag, event) {}


maxFontSizeEm: Size of the largest tag in the cloud in css 'em'. The smallest
   one's size is 1em so this value is the ratio of the smallest and largest
   sizes.

   default: 4


Styling:
--------
 The plugin adds the "tagcloudlink" class to the generated tag links. Note that
an "&nbsp;" is generated between the links too.


Originally based on DynaCloud v3 by
Johann Burkard
<http://johannburkard.de>
<mailto:jb@eaio.com>

CHANGES:
05 sept. 2008
- Improved normalization algorithm - better looking font sizes
- New settings: click, maxFontSizeEm
- Documentation

04 sept. 2008
- Initial version

*/

jQuery.fn.tagCloud = function(cl, givenOptions) { //return this.each( function() { //like a real jQuery plugin: run on on each element
   if (!cl || !cl.length)
      return this;

   // Default settings:
   var defaults = {
      sort: function (a, b) {return a.tag < b.tag ? -1 : (a.tag == b.tag ? 0 : 1)},//default sorting: abc
      click: function(tag) {},
      maxFontSizeEm: 4,
			gradient: null
   }

   var options = {};
   jQuery.extend(options, defaults, givenOptions);

   // calculating the max and min count values
   var max = -1;
   var min = cl[0].count;
   jQuery.each(cl, function(i, n) {
      max = Math.max(n.count, max);
      min = Math.min(n.count, min);
   });

   if (options.sort) {
      cl.sort(options.sort);
   }

   //Normalization helper
   var diff = ( max == min ? 1    // if all values are equal, do not divide by zero
                           : (max - min) / (options.maxFontSizeEm - 1) ); //optimization: Originally we want to divide by diff
                           // and multiple by maxFontSizeEm - 1 in getNormalizedSize.

	function getNormalizedSize(count) {
		return 1 + (count - min) / diff;
	}

  function getNormalizedColor(count) {
		if (!options["gradient"]) {
			return "";
		} else {
	    val = (count - min) / (max == min ? max : max - min);
			minColor = maxColor = null;
	
			options["gradient"].each(function(gradientPoint) {
				// minColor
				if (val >= gradientPoint['val']) {
					minColor = gradientPoint;
				}
				
				// maxColor
				if (!maxColor && val <= gradientPoint['val']) {
					maxColor = gradientPoint;
				}
			});
			
			minColor = minColor || options["gradient"].first();
			maxColor = maxColor || options["gradient"].last();
			
			multiplier = (maxColor['val'] - minColor['val']) != 0 ? 
				(val - minColor['val']) / (maxColor['val'] - minColor['val']) :
				1.0;

			r = Math.floor(minColor['r'] + multiplier * (maxColor['r'] - minColor['r']));
			g = Math.floor(minColor['g'] + multiplier * (maxColor['g'] - minColor['g']));
			b = Math.floor(minColor['b'] + multiplier * (maxColor['b'] - minColor['b']));
			return 'color: rgb('+r+','+g+','+b+')';
  	}
  }

   // Generating the output
   this.empty();
   for (var i = 0; i < cl.length; ++i) {
      var tag = cl[i].tag;
      var tagEl = jQuery('<span class="tagcloudlink" style="font-size: '
                           + getNormalizedSize(cl[i].count)
                           + 'em;' + getNormalizedColor(cl[i].count) + '">' + tag + '<\/span>')
                  .data('tag', tag);

      if (options.click) {
         tagEl.click(function(event) {
            event.preventDefault();
            options.click(jQuery(event.target).data('tag'), event);
         });
      }
      this.append(tagEl).append(" ");
   }
   return this;
//})
}